Many electrical devices are designed to be operable under battery power. Often, these electrical devices may be powered by an external power source or one or more batteries. Devices operable under battery power often provide circuitry for charging the batteries. This circuitry may be either internal to the device, integrated with an external power source circuit, or external to both the device and the external power source circuit.
The recent popularity of portable electronic devices such as portable computers, MP3 players, handheld video games, cellular telephones, and the like, has greatly increased the number of devices operable with rechargeable batteries. Consumers have become accustomed to the constant availability of the conveniences offered by these devices and may be reluctant to discontinue use in order to recharge the batteries. On the other hand, consumers prefer that the batteries always be fully charged such that the consumer may unplug the device at any time and have maximum runtime.
Accordingly, it is beneficial to have a method and a device to power an application load while charging a battery.